Electromagnetic relay with adjustable lever-relation



March 11, 1952 Q JORGENSEN 2,588,534

ELECTROMAGNETIC RELAY WITH ADJUSTABLE LEVER-RELATION Filed Sept. 27,1948 mvgsn TOR JAN I R R N JE AT T ORNEYS Patented Mar. 11, 1952ELECTROMAGNETIC RELAY WITH ADJUST- ABLE LEVER-RELATION Ander Ossian Jorgensen, Hallebergsvagen, Sweden, assignor to Telefonaktiebolaget L MEricsson, Stockholm, Sweden, a company of Sweden Application September2'7, 1948, Serial No. 51,445 In Sweden October 9, 1947 6 Claims.

The present invention relates to electromagnetic relays, and refersespecially to the kind known as marginal relays, i. e. such relays inwhich an adjustment of make-time, release time, make-current etc. may beeffected.

At production of a relay, which is to be used for a varying number offunctions, it is known to choose a suitable value of the lever relation,i. e. the relation between the movements of the armature right in frontof the pole piece and the movement of the armature or the associatedlever right in front of the lifting member of the contact springs.

With a definite lever relation, the makeand release valves of the relaywill naturally be unfavourable in quite a number of cases, andadjustment of the contact springs, the construction of the armature orthe pole stud must take place. According to the present invention thistedious and complicated operation can be avoided by arranging such alever for transmission of the movement of the armature to the liftingmember of the contact springs so that said lever relation or arm ratiocan be varied.

The invention will be described more clearly with reference to theaccompanying drawing. Figs. 1 and 2 show graphs of the properties of arelay at varying lever-relations. Fig. 3 shows a perspective view of arelay according to the invention with an adjustable lever. Fig. 4 showsa detail of the lever, and Fig. 5 a sliding stud for this lever. Fig. 6illustrates, by means of a side view of the relay according to Fig. 3,the movements of the armature and the lever.

A study of the properties of a relay in function of the lever-relation 1shows, that the make-time t1 varies according to Fig. 1. By make-time ismeant the time from the moment, when the circuit to the relay is closeduntil a certain pair of contacts has been actuated. A voltage V1 givesthe curve I a voltage V2 the curve |2 etc., whereby V1 V2 V3. The higherthe voltage, the shorter the make-time. It appears from the curves, thatthe regulation is good. By changing the lever-relation from b to a, themake-time t can be shortened from tit to tla at the same voltage V2.This also happens in case of makecurrent.

The release-time t2 of the relay in function of the lever-relation fappears from Fig. 2. By release-time is meant the time, which passesfrom the moment when the current to the relay has been broken until acertain pair of contacts has been actuated.

The curve 2| shows the release-time at a voltage V1 of the relay, thecurve 22 at a voltage V:

2 etc., whereby V1 V2 V3. At a normal leverrelation ,f a, a release-timetta is obtained at a voltage V1. By adjusting the relation 1', a changeof :30% of the release-time can usually be obtained without difficulty,which is a considerable adjustment for marginal relays.

The adjustable lever-arrangement shown in Fig. 3 has been applied to aflat-type relay. The lever arrangement can naturally also be used incase of other types of relays.

On a core 3| with a winding 32 and a pole-shoe 33, an armature 34 ismounted, which turns round a shaft 35.

which, at movement of the lever, respectively actuate the lifting pins31.

An L-shaped arm 4| is fixed to the armature 34, and overhangs the poleshoe 33. A tap 50 extends laterally from 4| and mounts a screw forlimiting the stroke of the armature. In a longitudinal slot 5| in thelever 39, an adjustable or sliding stud 42 is arranged having awedge-like lower end to bear on the upper arm of 4| When the armature 34operates, on energization of the winding 32, the arm 4| moves upwards.The stud 42 is thereby lifted and so is the lever 39, which by means ofthe screws 40 actuates the lifting pins 31 and the spring contact sets36. In order to obtain the smallest possible slippage during themovement of the armature between the stud 42 and the arm 4|, theadjustment path of movement of the stud lies in a geometric plane, whichpasses through the axis of the fulcrum 35 of the armature and thefulcrum 38 of the lever support, Fig. 6. Since the engagement pointbetween the stud 42 and the arm 4| during the operation of the armaturechanges in respect to the line through the shafts 35 and 38, theseconditions are fulfilled when the armature lies between the extremepositions, 1. e. makeand release position at the greatest possiblelever-relation.

In order to obtain the smallest possible slippage between the liftingpin 31 and the lifting screws 40, the angle between a line through therotating shaft 38 and the upper side of the lifting screw 40, and a linethrough the direction of movement of the lifting screws, is arranged tobe 90 when the armature is right between the extreme positions at thegreatest possible lever-relation.

In Fig. 5 a design of the stud 42 is shown.

One or more spring contact sets '36 are attached to the core in a wayknown per se.; These spring contact sets are each actuated by The studis inserted in a hole 52 at the end of the groove 5|, Fig. 4, on thelever 39. The grooves 62 in the stud will thus be directed by the edgesof the lever groove. The grooves 62 are made so that a certain frictionagainst the lever is obtained. v

Furthermore, the design is so arranged, that the adjustment path of thestud on the lever 'and the upper surface of the arm 4| are parallel whenthe armature is operated. A favourable adjustment is thereby obtained.This can be made at make-position of the relay. At constant movement ofthe spring set a dislocation of the adjusting stud only requires thatthe stroke of the armature be changed by adjusting the stop screw of thearmature. When the adjusting stud is moved along the arm, the stroke ofthe armature is continually changed with the lever-relation if the stopscrew is not moved. If the adjusting stud with its adjustment path isattached to the arm 4! of .thearmature and if the stop screw of thearmature is placed in the. adjusting stud similar results may beattained.

-I claim:

1. In an electromagnetic relay, in combination, a magnet having a core,contact springs supported adjacent said magnet, an armature. fulcrumed.to and associated with said core remote from and to actuate said springswhen the magnet is energized, a lift member for said springs, a leverinterposed between said armature and lift member and having a fixedfulcrum remote from the armature fulcrum and an actuating arm of fixedlength for actuating said lift member, a stud positioned tomove saidlever from said armature, and means whereby the stud may be adjustedtoward or from said lever fulcrum to change the activated arm of thelever.

.2. The relay asdefined. in claim 1 in which the adjustment path of saidstud lies on a line passing through said fulcrums when the. lever is inmidposition.

3. The relay asdefined in claim .2 in which the armature is providedwith a lever moving arm with a surface parallel to said line forengaging the stud in any of its adjusted positions.

4. In an electromagnetic relay, in combination, an elongated core, awinding intermediate the ends of said core, an armature fulcrumed to oneend of said core and having a part cooperating with the opposite end, anarm on said armature overhanging said opposite end and having anadjustable stop for cooperation therewith, a lever fulcrumed adjacentsaid winding and having an adjustable lifting screw intermediate itsends, a contact spring extending substantially parallel to said core andhaving an operating pin bearing on said lifting screw, a studintermediate the lever and overhanging arm to actuate the former fromthe latter, and means providing a path through which said stud may beadjusted to change the effective length of the actuated arm of thelever.

5. The relay as defined in claim 4 in which the parts are so constructedand arranged that the lever in midposition lies in a plane passingthrough the axes of the armature and lever and the surface of saidoverhanging arm provided for engagement by said adjustable stud isparallel to said plane.

6. The relay as defined in claim 5 in which the said plane is inclinedto the plane of said contact spring, said adjustable lifting screw beingarranged on. an axis normal to the plane of the spring.

ANDERS OSSIAN JORGENSEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 237,776 Reed Feb. 15, 1881749,814 Downs Jan. 19, 1904 1,246,625 Lundell Nov. 13. 1917'

